This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present invention. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present invention. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
In conventional subsea production and processing systems, monitoring is typically done by means of subsea sensors. A majority of conventional monitoring systems utilize pressure-temperature (PT) sensors. Such sensors collect production parameters at each sensing point in real-time to provide information on system health condition. For subsea processing, such as, but not limited to, pumping, compression and separation, subsea PT sensors can provide control signals necessary for proper operation. As a result, sensor failure may result in extended unplanned shutdown of the subsea processing system resulting in production loss. For example, if the PT sensor on a subsea separator fails, the whole subsea separation system may have to be shut down because the control system cannot operate without the signal from the PT sensor. Therefore, subsea PT sensors are critical for subsea production; however, their reliability is often insufficient for subsea fields because sensor failures result in high intervention costs in addition to production losses.
Conventional subsea PT sensors are not designed to be retrievable by a remotely operated vehicle (ROV). A monitoring system 100 is depicted in FIG. 1. System 100 includes a pipeline 101 which is designed to deliver product, such as, but not limited to, hydrocarbons in liquid or gaseous form, from one location to another. A sensor 103 is provided to monitor conditions within the interior region 105 of pipeline 101. Information collected by sensor 103 may be communicated to a control module or other known components via communication cable 107.
As depicted, a portion of sensor 103 is inserted through an aperture provided in pipeline 101. However, such a design is problematic. Sensor failures result in high intervention and repair costs in addition to production losses because the retrieval of a tree or production equipment is required to replace the failed sensor. To mitigate PT sensor failures, some known strategies call for ROV-installable external (“retrofit”) strain gauges to be clamped onto the tree to replicate the function of the failed pressure sensors. One such known strain gauge technology is capable of detecting relative pressure with an accuracy of 10 psi. However, the pressure gauge only provides a relative pressure reading and is therefore not suitable for applications requiring absolute pressure readings such as processing control.
Thus, there is a need for improvement in this field.